What the hell is going on here anyways?

What the hell exactly is going on here? I’ve talked about the machine I have for some time now but not fully explained what it is exactly that’s going on and why it’s such a bitch.

For starters, let’s recap how they work: For a given accelerator magnet, there is a wire wound many times around the barrel. When an electric current is passed through that wire, it is literally electrons circling the barrel. By the right hand rule, when an electron is moving, it creates a magnetic field. Because the wire is wound around the barrel, it creates that strong magnetic field inside the barrel itself.
If there happens to be a piece of iron in the barrel, the atoms within the iron will align themselves with the magnetic field and strengthen it. Now the wire and the iron are both acting as magnets and they will attract each other.

In an accelerator, the machine will turn on power to a given coil when the projectile is near that coil. It will pull the projectile into its center. Once the projectile reaches that center, it will turn off and allow the projectile to continue onwards.

Many of these magnets can be lined up where each one imparts a certain amount of energy on the projectile. Since there is a set force between the coil and the projectile and the projectile travels a set distance to reach the center of the coil, the work done (W = F*D) is a constant. Thus, every subsequent accelerating magnet imparts the same amount of energy on the projectile as did the first regardless of how fast the projectile is moving.

Minor explosion causes significant rework

You may have noticed that I've not posted for a while. Aside from an actual job that pays, I had a significant issue with the machine. I'd post pictures of what I'm about to describe but I'm not at my house and don't feel like waiting. Instead, here's picks of the chick working on... most just looking crazy while she cuts the mountings for her 3d light cube.

The explosion on the machine was more of a loud pop and some sparks. Never a good sign. In the end, it looks like one of the coils was touching the metal casing. I burned through it's enamel and took the voltage on the entire case up to 400V. When a wire from the optical sensors also touched the case, it fried about every piece of circuity in the device. Ever firing circuit, the computer, all the optical sensors. The only thing that survived was the charger (which is invincible as far as I can tell).

After a total catastrophe like that, one might as well rework the entire thing. I drew up new printed firing circuits. I made a new mount for the computer, I changed all but the very first accelerator magnet to be computer controlled, and finally I'm using shielded wire for all the sensors. Never again will I worry about EM noise, I'm shielding fucking everything.

As of yesterday, I finally have 4 accelerator gates working again. The machine was back up to 51m/s. This is about on-par with where we used to be. And of course now that I've enabled more control over certain parts and added EM protection, I think it'll be far more sustainable to expand.

Fine, I'll shield it

The blue line is actually the signal from the sensor. You can see it looks like shit. I'm getting very inconsistent firing out of the device. I think this is because the signals are getting scrambled. I didn't want to resort to using shielded conductors but it looks like I'll have to if I want to see much of anything at all come out of it.

Workspace is trashed; girlfirend unphased.

Got the 7th gate up and working. Now hitting 66m/s.

Earlier commenters have claimed that my workspace may not be trashed to shit on account of me going steady. I submit that my workspace is still totally trashed and simply that the girl is unphased by anything. Even LC circuits :P

(BTW, industrial machinery is an excellent differentiator of of relationship duration. Get laid in a room that has a mattress on the floor, a mounted electromagnetic rifle, a milling machine, 200lbs of parts, and sound proofed walls but wonder nothing off it: One night stand... Walk in and ask 'What the fuck is that?': Keeper.)

6th Accelerator: 62m/s, also damage testing

First, let's talk velocity: With the 6th gate easily installed and tuned, it's clear I have the right system working now. From the tuning, you can see that we're able to send projectiles up to 62 m/s (though we're more reliably at the 60m/s range).






Perhaps more interestingly though, I've also done an initial damage test. I used two tie plates, each about 0.9mm in thickness, riveted together. They should do a decent job of absorbing the impact and I don't expect the round to penetrate them yet. Once I have all the gates on, that'll be the goal.

From the photos you can see it did decent damage but as predicted didn't penetrate.

Relentless, inevitable progress

I've installed the 5th gate and gotten it working. There's still a problem with discharging while firing but for some reason the system generally recovers from that. I've half a mind to just start switching out parts of the 5th magnet, it's clearly the bad one. The odd part is that if I disconnect the computer from it, it stops. Yet if I put a scope on the output of the computer, it doesn't seem to be doing anything special (holding the line low, just like it's supposed to).



(Second picture is the waveform of the sensors. Good and clean, given they're quite a ways from the magnets.

Look, it's fucking complicated, ok

I did construct a brand spankin new firing circuit and mount it. It's now powered by one seriously el-cheapo 16bit pic chip (that I'm in love with). Problem is, I also changed the diodes I've been using and it seems like they'll blow out at the drop of a hat. Specifically, when the magnets tried firing while the system was charging (my most common issue). I'm not looking forward to fabricating and installing an entire second chip when I've blown all the sections of this one. For now, I'll try splicing more diodes in parallel with the existing ones (since they blow to the open-connection position).

On another interesting note, the 2nd accelerator gate was never quite the same after a chunk of wire fell into the firing circuit. Specifically, it would fire while charging unless there was a scope on a specific part of it, then it'd charge just fine. Seemed like a bit of a risk to keep it in so I switched it with one of the many firing circuits I'd previously made and am now not using.